Color photographic process



' Patented Nov. 5, 1940 coLon ruorooaarmo rnoonss was Schwarc, Brussels-Uccle, Belgium, assign or to Bla Gaspar, Hollywood, Calif.

No Drawing. Application September 30, 1939, Se,-

rial No. 297,407. In Great Britain October 1, r 1938 4 Claims.

The present invention relates to a color photographic process in which dye images are produced by color development in a layer which,

' si1ver halide emulsion layer by the destruction of a dye which during the exposure of the lightsensitive layer has the function of a filter dye.

Theprinclpal elements of the invention are:

halide emulsion layers of a light-sensitive multilayer material, ofa filter dye, l. e. of a dye which transmits certain colored light rays, required for the exposure of the silver halide emulsion layer or for the exposure of the silver halideemulsion layers, if any,

which have to be exposed through said layer, but absorbing other light rays which are not to be recorded by said layer or layers.

(b) The filter dye is non-removable by washing and is', if necessary, fixed to the layer by a precipitant. (c) The filter dye is destroyable by chemical means and if thus destroyed yields a compound which is capable of forming a dye by the process of colored development. (d) Destruction of the filter dye is carried out simultaneously with or prior to subjecting the latent image or a residual silver halide image or a bleached out silver image to a developer the oxidation products 'of which couple with the colorcoupler to form a dye image.

40 The invention has the advantage that instead of both a filter dye and a color coupler, one substance'only has to be incorporated into the lightsensitive emulsion. Mutual interaction of substances, of different kind becomes impossible. Furthermore, dyes can be fixed to an emulsion layer in a more efficient manner than can color formers. Dyes from which color couplers are obtained by destruction of the dye are superior to dyes which per se are color couplers, as they do not couple to form a-dye as long as they are not destroyed. For this reason it is unnecessary, after the formation of the dye image to remove the color former from the areas where it has not been transformed into dye.

V The invention consists in the process or pro- ,(a) The presence, in at least one of the silver ducing multicolor dye images by color development in which the filter dye present in at least one of the light-sensitive silver halide emulsion layers of a. multilayer material is capable of being destroyed and transformed into a color 5 coupler, and in which the light-sensitive material is exposed and after the first or second developmentor after transforming the silver image into silver halide, the filter dye is destroyed simultaneously with or prior to the color development 10 of silver halide. Dyes from various groups of dyes, such as azo dyes and dyes of the general formula cH-(cH=cH).-0H=c described in theco-pending application Ser. No. 240,860 filed November 16, 1938, by Bla Gaspar, are suitable for carrying out the process. Various methods may be used for converting the dye into the color coupler. p

Example-A double coated film and a single coated film are united to form a bipack. The single coated film carries an ordinary blue-sensitive silver halide emulsion layer. The double coated film carries on the same side of the transparent support an orthochromatic emulsion in superposition to a panchromatic emulsion layer. Both films are placed together with-the three light-sensitive emulsion layers between the-sup- 30 ports, the single-coated film being the front element of the bipack. 0f the two layers of the double coated rear element of the pack the orthochromatic layer is dyed yellow with 0.5 gram per sq. -m. of the yellow monoazo dye obtainable by coupling in soda-alkaline solution 1 mol diazotized sulfanilic acid with 1 mol 1.1'-[diphenylene- (4.4)l-bis-[3-methyl-pyrazolone-(5)] (see Beilstein, IVth ed., Suppl. Vol. XXIV, page 212). The panchromatic layer is dyed with 0.3 gram per sq. m. of the redviolet monoazo dyewhich is obtained by coupling in alkaline solution 1 mol of diazotized sulfanilic acid with 1 mol 1.5-di-hydroxynaphthalene (see Beilstein, IVth ed., Vol. VI, page 980). The bipack is exposed in the camera with the supportof the single coated film turned towards the lens. The two elements of the exposed bipack are separated and developed with an ordinary black and white developer and then fixed with hypo. The double coated film is treated thereafter with a solution of 1.5 parts sodium hydrosulfite and 0.1 part anthraquinone -p-sulfonic acid in parts of water, rendered slightly alkaline by the addition of sodium carbonate. After the dyes have been more or less decolorized, 55

' Water the fllmis rinsed inwater and treated for a minutes with a 10% aqueous solution of formaldehyde, again washed and treatedwith an acid cupric chloride solution which transforms the silver images into silver salt images. The film is then subjected to the action of a of the following formula:

A Parts, p-Dimethylamino aniline-hydrochloride- .2 Sodium carbonate 1,000

The silver images are removed in the known'ma'nner, for example with'Farmers reducer and atwo-color-negative is obtained in the rear element of the bipack. From the yellow azo dye there has been obtained by reduction with hydroemulsion layer with a coupler for yellow and havsensitive layer may be produced ing on the other side a green-sensitive layer, containing a coupler for magenta and a red-sensitive layer containing a coupler for bluegreen. By color developing the positive film, a positive in natural colors is obtained.

Instead of using color couplers in the positive material, there may be used dyes that act as filter dyes and yield. the color coupler after destruction. Thus the dyes used in the negative material described above may be employed for coloring the corresponding layers of the positive material. The blue-sensitive layer of the positive film may contain one of the known color couplers for yellow, such as a-ohloro-acetoacetic ester or a derivative thereof. Alternatively, the bluewithout any color coupler and the yellow dye formed with a color developer of the following formula:

e-Chloro-aceto-acetic ethyl grams 2 p-Dimethylamino-amine hydrochloride grams... 2 Acetone e ccs 20 Potassium carbonate grams 40 Water ccs 1,000

- This developer is applied to the single coated side of the positive film, or in the case in which all of the layers of the positive film are on the same side of the support with the blue-sensitive layer on top of the other layers, the action of the color developer is restricted to the top layer and development of the lower layers is continued with a color developer free from color couplers.

Whereas in the above example azo dyes have been used the following description shows that also other dyes which are destroyable to form a color coupler'may be used for carrying out the process.

A light-sensitive silver halide emulsion layer containing 1.5 grams per sq. m. of the yellow dye 4.4 -methenyl-bis- 1 (p-sulfophenyl) -3 -methyl- -.pyrazolone-5] is developed with an ordinary black and white developer containing sodium sulfite. The developer destroys the yellow filter dye. After removing the unexposed silver halide color developer by hypo, the'silver image is transiormedinto a silver halide image by an acid cupric chloride solution and thereafter th'e'illm is subjected to a developer containing p-dimethylamino-aniline.,; 1

The silver is removed by Farmer's reducer anda' redviolet dye image is obtained.

Instead of using an ordinary black and white film may lie-treated dip-dimethylamino-anilinei;

developer, the exposed rectly with an alkalin developer. .This developer acts to destroy the filter dye and to form the dye by the interaction of thecolor coupler thus obtained with the oxidation products of the developer. 'What is claimed is: 1. A process of producing by color development photographic dye images from-an exposed light-sensitive silver halide emulsion layer, said light-sensitive silver halide emulsion layer comprising a dye which is destroyable to a color coupler capable of forming a dye by reaction with the oxidation products of a photographic developer, the process comprising treating the layer with a dye destroying agent which acts to throughout-the layer and with a developer the formed to metallic silver.

2. A process of producing by color development photographic dye images from an exposed light-sensitive silver halide emulsion layer, said light-sensitive silver halide emulsion layer com-' prising a dye which is destroyable to a color cou pler capable of forming a dye by reaction with th oxidation products of a photographic developer, the process comprising treating the'layer with a solution containing both a dye destroying agent which-acts to transform the dye into said color coupler throughout the layer and a developer the oxidation products of which form a dye with the couplerat the places where silver halide is transformed to metallic silver.

3. A process of producing by color development photographic dye images from an exposed lightsensitive silver halide emulsion layer, said light-,- sensitve silver halide'emulsion layer comprising an azo dye which is destroyable to a color cou- .pler capable of forming a dye by reaction with 4. A process of producing by color development transform the dye into said" color coupler photographic dy images from an exposed lightsensitive silver halide emulsion layer in a multilayer material, said light-sensitive silver halide emulsion layer comprising a dye which is destroyable toa color coupler capable of forming a dy by reaction with the oxidation products of a photographic developer, the process comprising treating the multilayer material with a dye destroying agent which acts to transform the dye into said color coupler throughout the layer and with a developer the oxidation products of which form a dye with the coupler at the places where silver halide is transformed to metallic silver.

LAszLo SCHWARC.-

CERTIFICATE OF CORRECTION.

Patent No. 2,220,125. November 5, 1911.0.

LASZLO SCHWARC.

It is hereby certified that error appears 7 in the printed specification ion as follows: Page 1, seccf the above numbered patent requiring correct and that the said Letters 0nd column, line 58, for (Ll..l read -(l .Lu Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this ll th day of January, A. D. 1914i.

Henry Van Arsdale,

(Seal) Acting; Commissioner of Patents. 

